This invention relates generally to a camshaft follower arrangement having a modular camshaft follower assembly and more particularly to a camshaft follower arrangement and method for an internal combustion engine having a plurality of adjustable camshaft follower assemblies connected in fluid communication.
Camshaft followers are often used in internal combustion engines to provide an interface in the translation of rotary motion of a camshaft to linear motion of push rods associated with intake valves, exhaust valves and fuel injector pump. The push rods are frequently located between rocker arms associated with the intake and the exhaust valves and the camshaft followers and transfer motive force from the camshaft to open and close the intake and exhaust valves in accordance with the desired engine timing events. Push rods may also be located between a camshaft follower and a fuel injector pump and provide motive force for fuel injector pump actuation.
Typically, the camshaft followers are pivotally connected to the engine at a location in reasonable close proximity to the camshaft either individually or as an assembly. The position of the camshaft follower relative to the camshaft is critical and any deviation from nominal will effect various engine timing. It is important that engine timing events such as intake and exhaust valve opening and closing and fuel injector pump actuation occurs at a predetermined time and duration to achieve optimum operating conditions. Due to manufacturing tolerances, it is impossible to consistently achieve nominal camshaft follower positioning relative to the camshaft and accurately control timing events. In order to accommodate these deviations in the position of the camshaft follower from the nominal, adjustment of the camshaft follower relative to the camshaft is often required. Adjustments of individual or multiple camshaft followers using eccentric means, set screws and the like tend to be difficult to make. Such devices are also subject to inadvertent loosening during engine operation resulting in a deviation in the timing events from the desired and resulting in rough engine operation.
Lubrication of camshaft followers to reduce the friction at bearing interfaces with associated components and the lubrication of other components associated with engine valve actuation and fuel injector pump operation is required. Often a complex arrangement of tubing, nozzles and fittings are required in order to deliver a lubricating fluid to the appropriate locations. Such an arrangement is difficult to install on the engine, complicates assembly and disassembly of other components and is prone to leaking. It is therefore desirous to provide a sealed lubrication arrangement that is simple to manufacture and install on the engine.
It is known to provide camshaft follower assemblies for installation on internal combustion engines. Such assemblies are tailored to fit a specific location on an engine requiring that each engine has a plurality of differently configured assemblies. This requires that a plurality of different configured camshaft follower assemblies be inventoried and tracked. Further, each of such assemblies must be installed at a proper different location on the engine leading to some confusion and potential assembling problems.
The present invention is directed at overcoming one or more of the problems as set forth above.
In one aspect of the present invention a camshaft follower arrangement for an internal combustion engine having a camshaft is provided. The camshaft follower arrangement includes a modular camshaft follower assembly having a body having a first and second ends, a longitudinal bore extending between said first and second ends and a side mounting surface located between the first and second ends. The modular camshaft follower assembly has a shaft disposed in the longitudinal bore of the body and a plurality of camshaft following lever arms each having first and second spaced end portions. The camshaft following lever arms are connected at the first end portion to the shaft and pivotally movable relative to an axis of the shaft. The camshaft following lever arms are maintained at predetermined axially spaced apart locations along the shaft and extending radially from the shaft. The camshaft following lever arms are each actuatable at said second end portion by the camshaft. The camshaft follower arrangement includes a camshaft supporting structure and a shim pack having at least one shim and disposed between the side mounting surface and the camshaft supporting structure. The shim pack adjustably positions each of the camshaft following lever arms transversely relative to the camshaft and a plurality of fasteners connect the body to the camshaft supporting structure at a predetermined location relative to the camshaft.
In another aspect of the present invention a camshaft follower arrangement for an internal combustion engine having a camshaft and a plurality of substantially identical modular camshaft follower assemblies is provided. The camshaft follower arrangement has a plurality of bodies each having a first and second ends, a longitudinal bore extending between the first and second ends, and a side mounting surface located between the first and second ends. A plurality of shafts each having first and second ends and are disposed in the longitudinal bore of a respective body. The shafts each have an axially extending aperture opening at the first and second ends. A plurality of camshaft following lever arms having first and second spaced end portions are pivotally connected at the first end portion to a respective shaft. The camshaft following lever arms are maintained at predetermined axially spaced apart locations along the respective shaft. A camshaft supporting structure rotatively supports the camshaft. A first fluid passing conduit fluidly connects the first end of a first shaft of the plurality of shafts to the second end of a second shaft of the plurality of shafts and passes lubricating fluid flow between the axially extending apertures of the first and second shafts. A plurality of fasteners connects the plurality of bodies to the camshaft supporting structure and maintains the fluid passing conduit in connection with the first end of the first shaft and the second end of the second shaft.
In yet another aspect of the present invention a method of adjustably connecting each of a plurality of substantially identical modular camshaft follower assemblies to a camshaft supporting structure of an internal combustion engine is provided. The modular camshaft follower assemblies each have a body, a shaft having first and second ends and an axially extending aperture opening at the first and second ends of said shaft. The shafts are each connected to a respective body. Each of said camshaft follower module assemblies have a plurality of spaced apart camshaft following lever arms pivotally connected to the shaft at axially spaced apart locations on the shaft. The method comprises the steps of:
placing a first shim pack having at least one shim and a predetermined thickness between a side mounting surface of a body of a first modular camshaft follower assembly and a camshaft supporting structure; connecting the first modular camshaft follower assembly of said plurality to the camshaft supporting structure;
positioning a first fluid passing conduit in fluid passing communication with the axially extending aperture at the first end of the shaft of the first modular camshaft follower assembly;
positioning said first fluid passing conduit in fluid passing communication with an axially extending aperture opening at the second end of a shaft of a second modular camshaft follower assembly of the plurality of camshaft follower module assemblies;
placing a second shim pack having at least one shim and a predetermined thickness between a side mounting surface of the body of the second modular camshaft follower assembly and the camshaft supporting structure; and
connecting the second modular camshaft follower assembly to the camshaft supporting structure.